Refrigeration



March 1939- s. w. E..ANDERSSON I 2,150,411

REFRIGERATION Filed Oct. 20, 1936 5 Sheets-Sheet l v I INVENTOR.

MdMA/u/w QZF/ W L A; ATTORNEY.

Match-14, 1939- s. w. E. ANDERSSON 2,150,411

REFRIGERATION Filed Oct. 20, 1936 5 Sheets-Sheet 2 INVENTOR.

MATTORNEY.

March 14, 1939. 5 w ANDERSSQN 1 2,150,411

REFRIGERATION Filed Oct 20, 1936 s Sheets-Sheet 5 INVENTOR.

MATTORNEY.

Marchl4, 1939. y D R N 2,150,411

REFRIGERATION Filed Oct. 20, 1956 5 Sheets-Sheet 4 INVENTOR.

' 44 ATTORNEY.

Patented Mar. 14, 193 9 I t UNITED STATES PATENT OFFICE,

2,150,411 REFRIGERATION Sven W. E. Andersson, Evansville, Ind., assignor to Servel, Inc., New York, N. Y., a. corporation of Delaware Application October 20, 1936, Serial No. 106,502 9 Claims. (01. 62-5) My invention relates to refrigeration, and more paratus compartment l5. By heating the genparticularly to control mechanism for absorption erator l4 the refrigerant is expelled from the refrigeration apparatus. absorption liquid, condensed in a suitable con- It is an object of my invention to provide an denser, and then returned to the evaporator i improvement in control mechanism for a reto complete the refrigerating cycle- The 5 frigerator of the absorption type for regulating weakened absorption liquid from which the rethe minimum heat input to the refrigerator. frigerant has been expelled is conducted from The invention, together with the 'objects and the generator I4 to the absorber to absorb readvantages thereof, will become apparent as I frigerant gas.

next describe the invention as embodied in a con- The cabinet I2 is provided with a compartment 10 trol mechanism like that shown in my applica- I6 which extends upward from the lower comtion Serial -No. 758,195, filed December 19, 1934, partment l5 at the rear of the storage compart- (Patent No. 2,123,921, granted July 19, 1938) and ment II, and the absorber, condenser, and other the features of novelty which characterize my parts of the apparatus may be positioned in the invention will be pointed out with particularity in lower compartment l5 and the vertically extend- 15 the claims forming a part of this specification. ing compartment iii. In order to simplify the In the drawings, Fig. 1 is a front elevation, drawings, the last-mentioned parts have not been partly broken away, of a refrigerator embodying shown, their illustration not being necessary for my invention; Fig. 2 is a side elevation, partly an understanding of my invention.

broken away and in section, of the refrigerator The generator I4 is provided with a heating flue 20 shown in Fig. 1; Fig. 3 is an enlarged fragmenl1 and is adapted to be 'heatedby a gas burner tary front elevation of the control mechanism l8 which is arranged so that the flame produced shown in connection with the refrigerator illusthereby is directed into the lower end of the flue. trated in Figs. 1 and 2; Fig.4 is a sectional view A suitable combustible gas is delivered froma 5 taken at line 44 of Fig. 3 to illustrate parts of source of supply through conduit 20, gas filter the control mechanism more clearly; Fig, 5 is a 2|, control mechanism 22, and conduit 23 to the fragmentary sectional view taken at line 5-5 of burner l8.

Fig. 3; Figs. 6 and 7 are sectional views taken The control mechanism 22, which is interposed at linesv 6-6 and 11, respectively, of Figs. 3' between the burner l8 and filter 2| and like that and 8; Fig. 8 is a view similar to Fig. 3 with the shown in my application referred to above, is pro- 30 cover plate and internal parts of the control vided to control the flow of gas to the burner. mechanism removed fromthe casing; and Fig. 9 Referring to Figs. 4, 8 and 9, the control mechais a sectional view taken at line 9-9 of Fig. 8v nism comprises a casing 24 having; apertured with the internal parts removed from the casing. bosses 25 and 26 which form inlet and outlet Referring to Figs. 1 and 2 of .the drawings, I openings, respectively, for the combustible gas. 35

have shown my invention in connection with a The gas flows from the inlet opening at the boss e r a o O a continuous absb'rption yp gen- 25 through a passage 21 into a diaphragm chamerally as disclosed in Patent No. 1,609,334 to B. C. ber. 28, which is shown most clearly in Fig 4. von .Platen and C. G. Munters, in which an aux- Fromthe' diaphragm chamber 28 the gas passes iliary pressure equalizing gasis employed. This into a valve chamber 29 through a passage 30 refrigerator comprises a cooling element or formed in a bushing 3| which is threadedly seevaporator l0 disposed in a thermally insulated cured at the open end of the chamber 29. The compartment Ll which maya f -S orage gas then, passes from the valve chamber 29 space in the upper portion of a cabinet l2 and through a passage 32 to the outlet opening at the into which ac'cess'maybe had by a door I3. A boss 26.

. refrigerant fluid, such as ammonia, evaporates Referring to Fig. 4, the right hand side of the in the evaporator l0 and difiuses into an inert bushing 3| forms a valve seat which is adapted to pressure equalizing gas, such as hydrogen. The cooperate with a valve 33 having a triangularresulting gas mixtureof refrigerant and hydrogen V shaped stem 34. The stem 34 extends through flows from the evaporator I0 to an absorber (not the passage 30 into the diaphragm chamber 28 50 shown) in'which-the refrigerant is absorbed by a and is provided at its endwith an enlarged head suitable liquid absorbent, such as water. The 35. ,The valve 33 is urged or biased'toward its inert hydrogen gas is returned to theevaporator closed or seated position on the bushing 3| by a In, and the enriched absorption liquid is conhelical spring 36 disposed within the valve chamducted to a generator l4 disposed in a. lower apber 29. Mechanism, hereinafter to be described, 55

is provided to urge the valve away from the bushing 3| against the tension of the spring 36 to permit gas to flow from the diaphragm chamber 28 through the passage 30 into the valve chamber 29.

The diaphragm chamber 28 is enclosed by a flexible diaphragm 31 having the peripheral edge thereof secured between the open end of the casing 24 and a cover plate 38, a gasket 39 being provided to make the diaphragm chamber 28 gastight so that the flow of gas from this chamber to the outlet opening at the boss 26 is insured. To the central portion of the diaphragm 31 is secured a hub member 40 having an opening 4| extending therethrough. To the hub member is secured one face of an expansible diaphragm 42. A yoke member 42 which extends about and beyond the expansible diaphragm 42 is secured to the hub member 40 between the flexible diaphragm 31 and the expansible diaphragm 42. To a pin 44 fixed to a cross piece of the yoke mem ber 43 are pivotally connected the upper ends of levers 45 and 46. A member 41 is pivotally connected at 48 to the lower end of lever 45 and provided with a catch 49 adapted to engage the lower end of the lever 46. A substantially hairpin-shaped spring 50 is arranged between the levers 45 and 46 whereby the latter are urged apart with the catch 49 adapted to engage the lower end of the lever 46 to prevent the levers from freely moving apart. The lever 45 is positioned adjacent to the "expansible diaphragm 42 and provided with a small set screw 5| which is adapted to be contacted by the right hand face of the expansible diaphragm 42.

It will be noted that the expansible diaphragm 42 and opening 4| in the hub member 40 form a completely enclosed space. To the opening 4| of the hub member 40 is secured one end of a capillary tube 52, the opposite end of which is secured to a thermal bulb 53 positioned in thermal contact with the evaporator or cooling element 0, as shown in Fig. 2. The expansible diaphragm 42, capillary tube 52, and thermal bulb 53 constitute what is termed an expansible fluid thermostat which is filled with a suitable fluid which expands with an increase in temperature and becomes reduced in volume with a decrease in temperature.

During normal operation of the refrigerator the levers 45 and 46, which are maintained in fixed position with respect to each other and to the resilient diaphragm 31;cooperate with the expansible diaphragm 42 and the enlarged head 35 of the valve 33 to control the flow of gas to the burner l8. Thus, when the temperature of the evaporator l8 increases, the expansion of the -fluid within the diaphragm 42 will cause 'the latter to expand so as to move the levers 45 and 46 to the right and move the valve 33 away from its seat at the bushing 3|. Conversely, when the temperature of the evaporator It. decreases, the decrease in volume of the fluid within the bellows 42 will cause the latter to contract so as to move the levers 45 and 46 to the left and permit the valve 33 to move toward its seat at the bushing 3 It will now be understood that with the levers 45 and 46 in the position shown in Fig. 4, any movement of the expansible diaphragm '42 is effectively transmitted to the valve 33, the levers in effect acting'as a single lever or substantially a rigid motion transmitting linkage. In order that the capillary tube 52 will not appreciably affect any movement ofthe hub member 40 when the control will be hereinafter described, the portion thereof adjacent to the connection at the opening 4| of the hub member 48 is spiral shaped, as shown in Fig. 4.

To adjust the expansible diaphragm 42 at any desired position to flx the position of lever 46 with respect to the head 35 of the valve 33, the cover plate 38 is provided with structure, hereinafter to be described, whereby a pulley 54 can be rotated to move a shaft 55 axially toward or away from the hub member 40. The shaft 55 is recessed to receive a pin- 56 which is secured to the hub member 40 and provided with a shoulder.

against which the inner end of the shaft 55 is phragm 31 and expansible diaphragm 42 and yoke member 43 carried thereby toward the valve 33 and flx the lever 46 at the desired position with respect to the head 35 of the valve 33. The diaphragm 31 is normally bowed or biased toward the cover plate 38 so that, when the shaft 55 is axially moved toward the left, the flexible diaphragm 31 will of its own accord follow the shaft until it is adjusted to its desired position to fix the lever 46 with respect to the valve 33.

Although the temperature of the cooling element l0 may be controlled at the lower compartment 5 by a dial 51 formed on the cover plate 38 of the control mechanism and by employing a suitable control knob in place of the grooved pulley 54, it is preferred to employ the latter and provide suitable operating mechanism for controlling the refrigeratorat the upper com- 1 partment As shown in Figs. 1 and 2, an indicating scale or dial 58 is mounted on the front of the cooling element l0 and a cooperating adjustment knob 59 is provided which is fixed to a rod 6|] that extends rearwardly through the rear wall of the compartment into the vertical compartment l6. To the rod 60 is secured a grooved pulley 6| which is similar to the grooved pulley 54 and operatively connected therewith by a flexible endless wire 62 having a guide tube 63. It will thus be seen that when the knob 59 at the front of the cooling element is turned, the rod 60 and rotation of the grooved pulley 54 associated with the control mechanism 22.

The control mechanism 22 is so constructed that only a half turn of the adjustment knob 59 is required to obtain full range adjustment of the thermostat for normal operation of the refrigerator. As shown in Figs. 4 and 5, the inner end of the shaft 55 is provided with a flange having a spiral cam 64 formed thereon which extends about half-way or around the periphery thereof. The cam 64 is adapted to ride on a short radial arm 65 formed at the inner end of the pin 56, the arm 65 being so positioned that the cam 64 is adapted to ride on the arm only when the shaft 55 is moved more than a half turn or 180. A movement of more than a half turn is imparted to the shaft 55 when the adjustment knob 59 is turned a like amount in a clockwise direction, which, as shown in Fig. 1, will place the knob 59 in the position indicated Defrost on the indicating scale 58. When such a movement of more than a half turn is imparted to the shaft 55, the cam 64 rides on the radial arm 65 and causes the hub member 40 and flexible diaphragm 31 I ment, the lever. 46 contacts the head 35which is 64 on the shaft 55 is disengaged from the radial arm 65 formed on the pin 56.

With the lever or part 46 now engaged by the notch 66 of the member 41, the levers 45 and 46 will not be effective to open the valve 33 with a normal increase of the temperature of the cooling element Ill due to the fact thatthe lever 46 is closer to the lever 45 and spaced from the enlarged head of the valve 33 by the distance between the catch 49 and the notch 66. As the temperature of the cooling element l6 increases, the expansible diaphragm 42 expands and moves the levers and 46 about the pin 44 toward the head 35 of the valve 33. When the cooling element H] reaches an-abnormally high temperature, which temperature is preferably above the freezing temperature of water, the diaphragm 42 expands an abnormal distance toward the valve33 and moves the lever 45 such a'distance that a short arm 61 on the member 41 engages a stop 68 formed on a cross-piece of the yoke member 43. With continued movement of the lever 45 toward the valve 33 due to an abnormal expansion of the diaphragm 42, the member 41 is caused to rotate about the pivot 48 and against the tension of the spring 50 v perature of water sufflciently long to insure subin a clockwise direction, whereby the lower end of the lever 46 is released from the notch 66 and is engaged by the catch 49.

During the period of time the lever 46 is engaged by the .notch 66 on the'member 41 and does not positively control the valve 33, the valve 33 remains in its closed position providing the temperature of the evaporator I0 is sufficiently low, and the supply of gas to the burner I8 is reduced, as described. hereinafter, thereby decreasing the heating of the generator l4 and permitting the temperature of the cooling element III to increase. When the temperature of the cooling element increases to a value above the freezing temperature of water, frost that may have accumulated on the cooling element! will melt and can be, col-' lected in' any suitable manner. The controlmechanism is preferably adjusted so'that, when, the adjustment knob 59 is moved to initiate defrosting of the cooling element II), the latter will remain at a temperature above the freezing temstantially complete melting of frost which has accumulated on the cooling element l6.

When the member 41 is caused to move in a clockwise direction'so that the lever 46 is released Y from the notch 66 and engages the catch. 49, as

described above, the valve 33 is immediately moved to an open position to permit such heating of the generator N that the temperature of the cooling element I0 will decrease to a value in the normal operating range of the refrigerator. This normal value of temperature is determined, of course, by the position of the adjustment knob 58 at the upper half of the dial 58 to which it has been returned after being moved momentarily to-the lower half of the dial to initiate defrosting.

After the cooling element In reaches the. normal temperature at which it is adjusted to operate the control mechanism, the levers 45 and 46, which now are in the normal position shown in Fig. 4,

will be operativeto control the valve 33 in re-- sponse to temperature changes of the cooling element It to maintain the latter at a substan-' tially constant temperature. When frost has again accumulated on the cooling element. III to such an extent that defrosting is desired, the adjustment knob 59 is moved to the position of the dial 58 indicated Defrost and then returned to the upper half of the dial to a position at which it is desired that normal operation will resume after the defrosting has automatically terminated.

In starting the refrigerator, the adjustment knob 59 is turned to a definite position at the upper half of the dial 58 and combustible gas, which is adapted to discharge from the end of a tube 69, is ignited to provide a pilot flame for starting the burner l8, as shown in Figs. 1 and 2. Referring to Fig. 6, the tube 69 is connected at 16 to the lower end of a passage 1| formed in the casing 24, the upper end of which passage communicateswith a small chamber 12 which in turn is connected by a passage 13 with the diaphragm chamber 28. Within the chamber 12 is disposed a ball valve" which is normally maintained in its closed position by a helical spring 15. The front part of the casing 24 is recessed to receive a push button 16 which is provided with a stem 11 adapted to engage the ball valve 14. The push button 16 is normally urged outward by a helical spring 18 whereby thevalve 14 remains in its closed position.

When it is desired to provide a pilot flame for starting the burner l8, the push button 16 is pressed inward whereby combustible gas flows from the diaphragm chamber 28 through passage 13, small chamber 12, and passage 1| to the tube 69. A screw 19 extending into the passage 1| is to a heat conductive member 86 which is con- "J'nected to a safety device 86a,,as shown-in Fig. 2,

the device including a valve connected in conduit 23. After the device 86a becomes sufliciently heated the valve opens whereby gas is delivered to the burner i8 and is immediately ignited by the pilotfiame at the end of tube 691 An adjustment .screw 8| is provided at the front of the burner l8 to adjust the burner flame and hence the maximum heat input to the generator l4. This adjustment ispr'eferably made when the adjustment knob 59 in the compartment H is at a predetermined position, for example, the number three position of the dial 58.

It is also desirable to adjust theminimum heat input to the generator l4 to a value which is from the latter through passage 83 which communicates with the passage 32 at the outlet side of the casing 24. Referring to Fig. 7, the .quantity of gas flowing through the by-pass is controlled by a regulating screw84b having a plug 85aat the innerend thereof-which is movable axially in the passage 82 against the tension of .ahelical'spring 86a. By turning the screw 84b after removing the-outer screw 840, the plug 85::

can be positioned in the passage 82 to control the quantityof gas which can flow from the passage 8! into the passage 82 and thence through passage 83 to the burner I8.

In order to make the minimum flame adjustment for the burner l8, it is necessary to close the main valve 33. In many instances, particularly when a refrigerator is being installed, the

evaporator I8 is above a predetermined low temperature and it would require operating the refrigerator for a relatively long period of time in order to effect closing of themain valve 33 with the parts of the control mechanism 22 thus far described.

In accordance with my invention, the control mechanism 22 is so constructed and arranged that the main valve 33 can be closed at any time to adjust or check the minimum heat input to the generator l4. Referring to Figs. 4 and 5, the mechanism for closing the main valve 33 to check or adjust the quantity of gas flowing through the by-pass to provide the minimum heat input to the generator I4 is included in the structure provided on the cover plate 38. As shown, the shaft 55, which is provided with a recess to receive the pin 56, extends through a sleeve'84iof shorter length. The inner end of sleeve84 is adapted to bear against the flange on the shaft on which the cam 64 is formed, and. the outer end thereof is provided with a multi-sided enlarged head 85. The outer end of the shaft 55 is cut away, as indicated at 88, and the extreme threaded end is adapted to receive a clamping nut 81 for drawing the inner flanged end of the shaft 55 against the-inner end of the sleeve'84 and also securea cap 88 over the outer end of the shaft 55 and multi-sided head 85 of the sleeve 84. The grooved pulley 54 is positioned over the cap 88 and. secured thereto, as by a set screw 89. By rotating the grooved pulley 54, therefore, the shaft 55, sleeve 84, cap 88, and grooved pulley 54 are turned as a unit.

The sleeve 84, which may be termed an inner sleeve, is externally threaded and adapted to move axially within an internally threaded shorter outer sleeve 98. The outer sleeve 98 is also externally threaded and adapted to move axially within a threaded central opening formed in the cover plate 38. -As shown in Figs. 3 and 5,

the outer sleeve 98 is provided with an arm 9| having a recess at the outer end thereof adapted to receive a set screw 92 secured to the front of the cover plate 38. The arm 9| is also provided with a raised portion 93 which is in the path of movement of an inwardly extending projection 94 formed on the cap 88.

The external threads of the inner sleeve 84 and internal threads of the outer sleeve 98 are left-hand threads whereby, when the grooved pulley 54 is turned in a counter-clockwise directlon, the shaft 55 is moved axially toward the valve 33; and conversely, when the grboved pulley is turned in a clockwise direction, the shaft 55 is moved axially away from the valve 33. The left-hand threads per inch provided on the inner and outer sleeves. 84 and 98 are such that, for a. half turn of the'adjustment knob 59. and .a half turn of the grooved pulley 54, full range adjustment of the thermostat is pbtained for normal operation of the refrigerator. In other words,

for a half turn of the grooved pulley 54 the cam 84 at the inner end of the shaft 55 is not in operation and the expansible diaphragm 42 and levers 45 and 48 are moved toward and away from the valve 33 a distance corresponding to the axial movement of the shaft 55 and inner sleeve 84. This normal range of operation is indicated by the numerals 1 to 5 on'the indicating scale 51 on the cover plate 38 and indicating scale 58 in the upper compartment H offthe cabinet l2. For this particular half turn, the levers 45 and 46 are in the position shown in Fig. 4 and cooperate with the expansible diaphragm 42 and enlarged head 35 of the valve 33 to control the flow of gas to the burner l8 in response to the temperature of the cooling element ID, as described above. And the temperature at which the cooling element is maintained is determined by the position of the expansible diaphragm 42 and levers 45 and 46 with respect to the valve 33, which temperature is indicated by the position of the adjustment knob 59 in the upper compartment II. By providing the raised portion 93 on the arm 9|, the inwardly extending projection 94 on the cap 88 will limit the extent of counterclockwise movement of the adjustment knob 59 so that the highest end of the cam 84 will not strike the radial arm 65 and thus injure parts of the control mechanism 22 within the casing 24.

When the adjustment knob 59 is turned in a clockwise direction past the numeral 5 on the indicating scale 58, axial movement is imparted to theshaft 55 in a direction away from the valve 33. This places the adjusting knob 59 in the lower part of the indicating scale marked Defrost. Although the shaft 55 is moved axially away from the valve 33 with such clockwise movement of the adjustment knob 59, the cam 64 now becomes effective and rides over the radial arm and forces the hub member .48 and flexible diaphragm 3'! and parts carried thereby an abnormal distance toward the valve 33. This abnormal movement of the diaphragm 31 toward the valve 33 is obtained by making the pitch of the cam 64 relatively high so that movement of the resilient diaphragm 31 toward the valve is effected even though the shaft 55 is being moved away from the valve 38. After the levers 45 and 48 have been moved closer together due to such abnormal movement of the diaphragm 31, as de 4 scribed above, the adjustment knob 59 is returned to the desired position at the upper half of the indicating scale 58 Whichwill determine the low temperature at which the cooling element l8 will be maintained after defrosting has automatically 0 terminated. With such return movement of the adjustment knob 59, cam 84 no longer cooperates with the radial arm 85 and the flat portion of the flange on which the cam is formed bears against the hub member 48. One complete turn of the adjustment knob may be considered effective to impart an axial movement to the expansible diaphragm 42 and levers 45 and 46 in a normal operating range to determine the temperature at which it is desired to maintain the evaporator 18 and to move the lever 46 from its normal position at catch 49 to its second position at notch 68. I

The outer sleeve 98 is normally so positioned within the opening inthe cover plate 38 that the arm 9| bears lightly against the front cover plate 38 and is locked in position by the set screw 92, as shown most clearly in Fig. 3. The inner sleeve 84 is so positioned axially with respect to the outer sleeve 98 that normal control of the refrigerator, as well as defrosting thereof, will be effective in the manner just described. The external threads formed on the outer sleeve 98 and at the opening of the cover plate 38 are righthand threads.

In order to close the valve 33 to adjust or regulate the quantity of gas flowing through the bypass passages 8|, 82, and 83, the set screw 92 on the cover plate 38 is loosened and the arm 9| is turned counter-clockwise one complete revolution 4 until the arm strikes the set screw 92. With such movement of the arm 9| an axial movement is imparted to the outer sleeve 93 in a direction away from the valve 33, and, due to the frictional engagement betweenthe outer sleeve 90 and inner sleeve 84, the entire structure provided on the cover plate .38 is moved in a direction away from the valve 33 along with the outer sleeve 90. The number of right-hand threads per inch formed on the sleeve 90 and opening in the cover plate 38 are less than the number of left-hand threads per inch on the outer sleeve 90 and inner sleeve 84, so that the axial movement effected by the outer sleeve 90 is greater than that effected by the inner sleeve 84 for a given rotation of the sleeves. The number of threads per inch formed on'the sleeve 90 and opening is preferably such that, with one complete revolution of the arm 9|, the shaft 55 moves axially away from the valve 33 a suflicient distance'to cause the resilient diaphragm 31 to bow toward the cover plate 38 and permit the valve 33 to close. The axial movement imparted to the outer sleeve 90, therefore,

permits the expansible diaphragm 42 to move be-' yond the normal operating range in which movement thereof is effected by the adjustment knob 59.

With the valve 33 in its closed position, the flow of gas through the by-pass passages can be adjusted, as described above, and the arm 3| then rotated in a clockwise direction to its normal position at the set screw 92. With the arm 9| locked in position by the set screw 32, the shaft 55 is again in its normal position whereby the refrigerator can be controlled by means of the adjustment knob 59 in the upper compartment H.

In view of the foregoing, it will be understood that I have provided a control mechanism which efiectively controls the flow of gas to the burner in response to a temperature condition affected by the cooling element, permits at will the instigation of defrosting which terminates automatically, closed at any time so that the minimum heat input to the generatorcan be adjusted by regulating the flow of gas through the by-pass passage provided around the main valve. By providing the shaft 55 with a recess to receive the-pin .53 secured to the hub member 40, the resilient diaphragm'3l is always guided with any axial movement of the shaft 55, so .that any cooking of the diaphragm tending to'injure the latter is avoided.

Although I have shown my improved control mechanism in connection with a particular type of refrigerator, I do not wish to be limited to the particular arrangement set forth, and I intend in the following claims to cover all modifications which do notdepart from the spirit and scope of my invention.

What is claimed is: v

1. In an absorption type refrigerator including a cooling element and a generator adapted to be heated by a fluid fuel burner, a main valve for controlling flow of fuel to said burner, a by-pass for fuel around said main valve, an adjustable valve in said by-pass, structure comprising asingle thermostat normallypperative to regulate said main valve to maintain said cooling element at a substantially constant, temperature, said structure being capable of modifying the normal and also enables the main valve to regulation of said main valve so that the latter is open only upon an abnormally high increase in temperature and operative to resume said normal regulation responsive to the abnormally high temperature, means operative to adjust said structure to determine the substantially constant temperature at which it is desired to maintain said cooling element and to cause said structure to modify said normal regulation of said main valve, and additional means operative to adjust said structure irrespective of the temperature of said cooling element for closing said main'valve so that adjustment of said by-pass valve can be effected at will to regulate thesize of the minimum flame produced by said burner.

2. In an absorption type refrigerator including a cooling element and a generator adapted to be heated by a fluid fuel burner, a valve for controlling flow of fuel to said burner, structure comprising a single thermostat normally operative to regulate said valve to maintain saidcooling element at a substantially constant temperature, said structure being capable of modifying the normal regulation of said valve to reduce the flow of fluid fuel to said burner and operative to resume said normal regulation responsive to an abnormally high increase in temperature, means operative to adjust said structure in a normal operating range to determine the substantially constant temperature at which it is desired tov determined temperature and, while said structure is in said normal operating range, and additional means operative to adjust said structure beyond said normal operating range for closing said valve while said cooling element is above the predetermined temperature.

3. In an absorption type refrigerator includinga cooling element and a generator adapted to be heated by a fluid fuel burner, a main valve for controlling flow of fuel to said burner, a bypass for fuel around said main valve, anadjustable valve in said by-pass, a thermostat element normally operative responsive to a temperature condition affected by said cooling element, structure operatively associating saidthermostat element and said main'valve so that'the flow of fuel is increased and decreased upon increase and decrease respectively of temperature, said structure being adjustable to modify said operative relation of said thermostat element and. said main valve so that the flow of fuel is increased only upon an abnormal rise-of temperature and operative to terminate said modified operative main valve irrespective of said temperature condition, so that adjustment of said by-p'ass valve can be effected at will to regulate the size of the minimum flame produced by said burner.

4. In an absorption type refrigerator including be heated by a fluid fuel burner, a mainwalve-l'fv for controlling the flow of fuel to said burr Lena by-pass for fluid fuel around said main valve, "an adjustable valve in said by-pass, structure a cooling element and a generator adapted to normally responsive to a temperature condition .aifected by said cooling element for controlling said main valve to maintain a normally produced condition of temperature, said controlling means including a part in its normal position, said part being movable from its normal position to a second position to modify the control of said main valve to permit said cooling element to increase to an abnormally high temperature, said structure being operative when said cooling element increases to the abnormally high temperature to move said part back to its normal position so that said structure is operative to resume maintaining a normally produced condition of temperature, means operative to adjust said structure in a normal operating range to determine the normally produced condition of temperature and to cause said part to move from its normal positionto the second position, said structure being so constructed and arranged that in the normal operating range said main valve is normally open when the condition of temperature is above a predetermined value, and additional means operative to adjust said structure beyond the normal operating range for closing said main valve when the condition of temperature is above the predetermined value, so that adjustment of said by-pass valve can be effected to regulate the size of the minimum flame produced by said burner.

5. In an absorption type refrigerator including a cooling element and a generator adapted to be heated by a fluid fuel burner, a main valve for controlling the flow of fuel to said burner, a by-pass for fuel around said main valve, an adjustable valve in said by-pass, structure normally responsive to a temperature condition aifected by said cooling element for controlling said main valve to maintain a normally produced condition of temperature, said structure being capable of modifying the normal regulation of said main valve so that the latter is open only upon an abnormal increase in temperature and operative to resume said normal regulation responsive to said abnormally high temperature, a part having an opening, and means including an outer sleeve member in threaded engagement with .the

.opening and an inner sleeve member in threaded engagement with said outer member for adjusting said structure, the axial movement effected by said outer member being greater than that effected by said inner member for a given rotation of said members, rotation of said inner mem-- her being operative to adjust said structure in a normal operating range to determine the normally produced condition of temperature and to cause said structure to modify said normal regulation, said structure being so constructed and arranged that said main valve is open when said cooling element is above a predetermined temperature and while'said structure is in the nor- I imal operating range, rotation of said outer mem- .ber being operative to adjust said structure beyondthe normal operating range for closing said main valve while said cooling element is above the predetermined temperature, so that adjustment of said by-pass valve can be effected to regulate the size of the minimum flame produced by saidbu'rner.

6. In anabsorption type refrigerator including a cooling element and a generator adapted. to be heated by a fluid fuel burner, a main valve having a stern for regulating the flow of gas to said burner, a by-pass for fluid fuel around said main valve, an adjustable valve in said by-pass, means tively associated with said stem, said part being movable toward said stem and said biasing means to cause said stem to contact and force said part to assume a second position and also movable away from said stem to a position in a normal operating range, the movement of said part from its normal position being effective to alter the normal control of said main valve so that said cooling element will increase to an abnormally high temperature, the expansion of fluid within said fluid thermostat element being effective when said cooling element reaches the abnormally high temperature to move said part back to its normal position so that the latter is operatively associated with said stem to control said main valve, means operative to adjust said structure in the normal operating range to determine the substantially constant temperature at which it is desired to maintain said cooling element and to cause said part to assume the second position to alter the normal control of said main valve, said structure being so constructed and arranged that said main valve is open when said cooling element is above a predetermined temperature and while said structure is in the normal operating range, and additional means operative to adjust said structure away from said main valve and beyond the normal operating range to permit said biasing means to close said main valve while said cooling element-is above a predetermined temperature, so that adjustment of said by-pass valve can be effected to regulate the size of the minimum flame produced by said burner.

7. In a refrigerator including a system having an evaporator for cooling and a'heated generator ing movement of said primary adjusting means to a relatively small range, and mechanism for bodily moving said body beyond the range possible with the primary adjusting means to limit flow-of fuel to by-pass flow when said body is abnormally expanded, and means to adjust bypass fiow.

8. In a refrigerator including a system having an evaporator for cooling and a heated generator and having a heater for heating the generator and a control device for regulating flow of fuel to the heater, said control device including main flow and by-pass structure, arr actuating device including an expansible and contractible body, primary adjusting rotary means for bodily moving said body, means limiting movement of said primary adjusting rotary means to less than 360, and mechanism including rotary means for bodily moving said bodybeyond the range possible with the primary adjusting rotary means to limit flow of fuel to by-pass flow when said body is abnormally expanded, and means to adjust by-pass flow.

9: In a refrigerator including a system having an evaporator for cooling and a generator, a heater for heating the generator anda control device for controlling rate of energy supply to the heater, the control device including structure to supply energy to the heater at a main rate and at a reduced rate, means including a thermostat element tor operating the control device to control the main rate'oi energy supply, primary adjusting means for adjusting the thermostat element, means limiting movement of said primary adjusting means to a relatively small range.

and mechanism for adjusting the thermostat element beyond the range possible with said primary adjusting means to limit the energy supply to the reduced rate when the thermostat element is subject to a. temperature above a. predetermined value, and means to adjust the reduced rate of energy supply.

SVEN- W. E. ANDERSSON. 

